bug#47348: Possible bug coreutils : no cat command

[Luís]

    In a reinstallation of Linux Mint 20 ( based on the ubuntu 20 focal fossa 
), I found that the cat command, supported by the Coreutils package 
(8.30-ubuntu2) is no longer working. I tried to reinstall ( just reinstall, 
because purge breaks the system, so I couldn't test removing possibly buggy 
settings ), then I tried to reinstall all dependencies on it. Everything 
useless. The return of the cat is totally speechless. I will now risk a version 
downgrade ( for bionic, the only one available ), but due to the risk of 
running out of functional computer, I decided to send this message first. I 
additionally noticed flaws in the synaptic interface and random error warnings 
from apt, each time a different malfunction, but this may have nothing to do 
with coreutils. I just thought it was good to report.